Light-emitting device

ABSTRACT

A light-emitting device comprising: a supportive substrate; a transparent layer formed on the supportive substrate, and the transparent layer comprising conductive metal oxide material; a light-emitting stacked layer comprising an active layer formed on the transparent layer; and an etching-stop layer formed between the light-emitting stacked layer and the supportive substrate and contacting the transparent layer, wherein a thickness of the etching-stop layer is thicker than that of the transparent layer.

RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 14/663,544, filed on Mar. 20, 2015, which is adivision application of U.S. patent application Ser. No. 13/175,698,filed on Jul. 1, 2011, which claims the benefit of provisionalapplication No. 61/389,286, filed on Oct. 4, 2010; the contents of whichare incorporated herein by reference in their entirety.

BACKGROUND

Technical Field

The present application relates to a light-emitting device, and moreparticularly, to a light-emitting device having an etching-stop layer.

Description of the Related Art

Light-emitting diodes (LEDs) have been applied widely in optical displaydevices, traffic signals, data storing devices, communication devices,illumination devices, and medical apparatuses. In the conventional LED,a metal current-spreading layer, such as Ti/Au or Cr/Au layers, isformed between the substrate and the light-emitting stacked layer.However, the metal current-spreading layer absorbs light and results inlow light-emitting efficiency of the LED.

SUMMARY OF THE DISCLOSURE

A light-emitting device comprising: a supportive substrate; atransparent layer formed on the supportive substrate, and thetransparent layer comprising conductive metal oxide material; alight-emitting stacked layer comprising an active layer formed on thetransparent layer; and an etching-stop layer formed between thelight-emitting stacked layer and the supportive substrate and contactingthe transparent layer, wherein a thickness of the etching-stop layer isthicker than that of the transparent layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures are included to provide easy understanding ofthe application, are incorporated herein, and constitute a part of thisspecification. The drawings illustrate embodiments of the applicationand, together with the description, serve to illustrate the principlesof the application.

FIGS. 1A-1F illustrate flow charts of a manufacturing process of alight-emitting element in accordance with an embodiment of the presentapplication.

FIG. 2 illustrates a cross-sectional view of a light-emitting element inaccordance with another embodiment of the present application.

FIG. 3 illustrates a cross-sectional view of a light-emitting element inaccordance with another embodiment of the present application.

FIG. 4 illustrates a cross-sectional view of a light-emitting device inaccordance with an embodiment of the present application.

FIG. 5 illustrates a cross-sectional view of a light-emitting device inaccordance with another embodiment of the present application.

FIG. 6 illustrates a schematic diagram of a light-generating device inaccordance with an embodiment of the present application.

FIG. 7 illustrates a schematic diagram of a back light module inaccordance with an embodiment of the present application.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of present application will be described in detail andsketched in figures. The same or similar parts will be shown with thesame numbers in every figure and the specification.

FIGS. 1A-1F are the flow charts of a manufacturing process of alight-emitting element 1. As FIG. 1A shows, there are a growth substrate10 and a light-emitting stacked layer 12 formed on the growth substrate10. The light-emitting stacked layer 12 includes a first semiconductorlayer 122; an active layer 124 formed on the first semiconductor layer122; and a second semiconductor layer 126 formed on the active layer124, wherein the polarities of the first semiconductor layer 122 and thesecond semiconductor layer 126 are different. A plurality of conductiveparts 20 is formed on the second semiconductor layer 126. A temporarysubstrate 14 is formed on the light-emitting stacked layer 12 and theplurality of conductive parts 20. As FIG. 1B shows, the growth substrate10 is removed and a plurality of contact parts 16 is formed under thefirst semiconductor layer 122. A transparent layer 18 is formed underthe first semiconductor layer 122 and covers the plurality of contactparts 16. An etching-stop layer 11 is formed under the transparent layer18 and a reflective layer 13 is formed under the transparent layer 18and covers the etching-stop layer 11, as FIG. 1C shows. A supportivesubstrate 17 is attached to the reflective layer 13 by a bonding layer15, as FIG. 1D shows. As FIG. 1E shows, the temporary substrate 14 isremoved and a portion of the second semiconductor layer 126 and theactive layer 124 is removed to expose a portion of the firstsemiconductor layer 122. A through-hole 19 is formed on the exposedportion of the first semiconductor layer 122 and extends to thereflective layer 13 to expose a portion of the etching-stop layer 11.The top surface of the second semiconductor layer 126 is roughened toform a rough surface. A first electrode 21 is formed on the exposedportion of the first semiconductor layer 122 and fills the through-hole19 to electrically connect with the etching-stop layer 11. A secondelectrode 22 is formed on the top surface of the second semiconductorlayer 126 such that a light-emitting element 1 is formed as shown inFIG. 1F. The second electrode 22 electrically connects with theplurality of conductive parts 20.

The supportive substrate 17 can support the light-emitting stacked layer12 and other layers or structures formed thereon. The material of thesupportive substrate 17 can be transparent material and highthermal-dissipative material. The transparent material includes but isnot limited to sapphire, diamond, glass, epoxy, quartz, acryl, Al₂O₃,ZnO, or AlN. The high thermal-dissipative material includes but is notlimited to Cu, Al, Mo, Cu—Sn, Cu—Zn, Cu—Cd, Ni—Sn, Ni—Co, Au alloy,diamond like carbon (DLC), graphite, carbon fiber, metal matrixcomposite (MMC), ceramic matrix composite (CMC), polymer matrixcomposite (PMC), Si, IP, ZnSe, GaAs, SiC, GaP, GaAsP, ZnSe, InP, LiGaO₂,or LiAlO₂. The bonding layer 15 can adhesively connect the supportivesubstrate 17 and the reflective layer 13 and further includes aplurality of sublayers (not shown). The material of the bonding layer 15can be insulating material and conductive material. The insulatingmaterial includes but is not limited to polyimide (PI), benzocyclobutene(BCB), perfluorocyclobutane (PFCB), MgO, Su8, epoxy, acrylic resin,cyclic olefin copolymer (COC), polymethyl methacrylate (PMMA),polyethylene terephthalate (PET), polycarbonate (PC), polyetherimide,fluorocarbon polymer, glass, Al₂O₃, SiO_(x), TiO₂, SiN_(x), orspin-on-glass (SOG). The conductive material includes but is not limitedto ITO, InO, SnO, CTO, ATO, AZO, ZTO, GZO, ZnO, AlGaAs, GaN, GaP, GaAs,GaAsP, IZO, Ta₂O₅, DLC, Cu, Al, In, Sn, Au, Pt, Zn, Ag, Ti, Ni, Pb, Pd,Ge, Cr, Cd, Co, Mn, Sb, Bi, Ga, Tl, Po, Ir, Re, Rh, Os, W, Li, Na, K,Be, Mg, Ca, Sr, Ba, Zr, Mo, La, Ag—Ti, Cu—Sn, Cu—Zn, Cu—Cd, Sn—Pb—Sb,Sn—Pb—Zn, Ni—Sn, Ni—Co, Au alloy, and so on. The reflective layer 13 canreflect the light emitted from the light-emitting stacked layer 12. Thematerial of the reflective layer 13 includes but is not limited to Cu,Al, In, Sn, Au, Pt, Zn, Ag, Ti, Ni, Pb, Pd, Ge, Cr, Cd, Co, Mn, Sb, Bi,Ga, Tl, Po, Ir, Re, Rh, Os, W, Li, Na, K, Be, Mg, Ca, Sr, Ba, Zr, Mo,La, Ag—Ti, Cu—Sn, Cu—Zn, Cu—Cd, Sn—Pb—Sb, Sn—Pb—Zn, Ni—Sn, Ni—Co, Aualloy, and so on. The etching-stop layer 11 can conduct current andprotect the reflective layer 13 from being damaged. The material of theetching-stop layer 11 includes but is not limited to conductive materialsuch as Cu, Al, In, Sn, Au, Pt, Zn, Ag, Ti, Ni, Pb, Pd, Ge, Cr, Cd, Co,Mn, Sb, Bi, Ga, Tl, Po, Ir, Re, Rh, Os, W, Li, Na, K, Be, Mg, Ca, Sr,Ba, Zr, Mo, La, Cr—Au, Ag—Ti, Cu—Sn, Cu—Zn, Cu—Cd, Sn—Pb—Sb, Sn—Pb—Zn,Ni—Sn, Ni—Co, Au alloy, Ge—Au—Ni, AlGaAs, GaN, GaP, GaAs, GaAsP, and soon. The transparent layer 18 can improve current spreading, form theomnidirectional reflector (ODR) with the reflective layer 13 to enhancethe probability of reflecting the light generated from thelight-emitting stacked layer 12, and protect the light-emitting stackedlayer 12 from being damaged by the element diffused from the material ofthe reflective layer 13. It can further include a plurality of sublayers(not shown). The material of the transparent layer 18 can be insulatingmaterial and conductive material. The insulating material includes butis not limited to PI, BCB, PFCB, MgO, Sub, epoxy, acrylic resin, COC,PMMA, PET, PC, polyetherimide, fluorocarbon polymer, glass, Al₂O₃,SiO_(x), TiO₂, SiN_(x), or SOG. The conductive material includes but notlimited to ITO, InO, SnO, CTO, ATO, AZO, ZTO, GZO, ZnO, AlGaAs, GaN,GaP, GaAs, GaAsP, IZO, Ta₂O₅, or DLC. The transparent layer 18 also canconduct and spread current when it is conductive.

The plurality of contact parts 16 can conduct and spread current. Eachof the plurality of contact parts 16 is independent from each other. Itcan further include a plurality of sublayers (not shown). The materialof the plurality of contact parts 16 includes but is not limited toconductive material such as Cu, Al, In, Sn, Au, Pt, Zn, Ag, Ti, Ni, Pb,Pd, Ge, Cr, Cd, Co, Mn, Sb, Bi, Ga, Tl, Po, Ir, Re, Rh, Os, W, Li, Na,K, Be, Mg, Ca, Sr, Ba, Zr, Mo, La, Ge—Au, Cr—Au, Ag—Ti, Cu—Sn, Cu—Zn,Cu—Cd, Sn—Pb—Sb, Sn—Pb—Zn, Ni—Sn, Ni—Co, Au alloy, Ge—Au—Ni, AlGaAs,GaN, GaP, GaAs, GaAsP, and so on. The shape of each of the plurality ofcontact parts 16 can be triangle, rectangle, trapezoid, circle, and soon. The diameter of the circle contact part, for example, can be 3˜15μm, preferably 6˜10 μm. The ratio of the area of the plurality ofcontact parts 16 to the area of the top surface of the active layer 124is about 0.5˜6%, preferably 1˜3%. To improve the current spreading, thearea of some of the plurality of contact parts 16 near the corners ofthe transparent layer 18 is larger than that of the other contact parts.The distance between each of the plurality of contact parts 16 dependson the thickness of the first semiconductor layer 122. When thethickness of the first semiconductor layer 122 is about 3 μm, forinstance, the distance between each of the plurality of contact parts 16is about 20˜40 μm. The thinner the thickness of the first semiconductorlayer 122 is, the smaller the distance between each of the plurality ofcontact parts 16 is. The plurality of contact parts 16 can be arrangedinto two or three lines between any two adjacent conductive parts 20 toimprove current spreading. Moreover, the plurality of contact parts 16is not covered by the second electrode 22 and the plurality ofconductive parts 20. Namely, the second electrode 22 and the pluralityof conductive parts 20 are not located right above the plurality ofcontact parts 16.

The semiconductor stacked layer 12 can generate light and includesemiconductor material containing more than one element selected from agroup consisting of Ga, Al, In, As, P, N, Zn, Cd, and Se. The first andsecond electrodes 21 and 22 are for receiving external voltage. Thematerial of the first and second electrodes 21 and 22 can be transparentconductive material and metal material. The transparent conductivematerial includes but is not limited to ITO, InO, SnO, CTO, ATO, AZO,ZTO, GZO, ZnO, AlGaAs, GaN, GaP, GaAs, GaAsP, IZO, Ta₂O₅, or DLC. Themetal material includes but is not limited to Cu, Al, In, Sn, Au, Pt,Zn, Ag, Ti, Ni, Pb, Pd, Ge, Cr, Cd, Co, Mn, Sb, Bi, Ga, Tl, Po, Ir, Re,Rh, Os, W, Li, Na, K, Be, Mg, Ca, Sr, Ba, Zr, Mo, La, Cr—Au, Ag—Ti,Cu—Sn, Cu—Zn, Cu—Cd, Sn—Pb—Sb, Sn—Pb—Zn, Ni—Sn, Ni—Co, Au alloy, and soon. The plurality of conductive parts 20 can conduct and spread current.The material of the plurality of conductive parts 20 can be transparentconductive material or metal material. The transparent conductivematerial includes but is not limited to ITO, InO, SnO, CTO, ATO, AZO,ZTO, GZO, ZnO, AlGaAs, GaN, GaP, GaAs, GaAsP, IZO, Ta₂O₅, or DLC. Themetal material includes but is not limited to Cu, Al, In, Sn, Au, Pt,Zn, Ag, Ti, Ni, Pb, Pd, Ge, Cr, Cd, Co, Mn, Sb, Bi, Ga, Tl, Po, Ir, Re,Rh, Os, W, Li, Na, K, Be, Mg, Ca, Sr, Ba, Zr, Mo, La, Cr—Au, Ag—Ti,Cu—Sn, Cu—Zn, Cu—Cd, Sn—Pb—Sb, Sn—Pb—Zn, Ni—Sn, Ni—Co, Au alloy, and soon.

FIG. 2 shows a light-emitting element 2 similar to what is shown inFIG. 1. The difference is that a portion of the light-emitting stackedlayer 12 and the transparent layer 18 are removed to expose at least aportion of the reflective layer 13 and the etching-stop layer 11. Thefirst electrode 21 is formed on the exposed portion of the reflectivelayer 13 and the etching-stop layer 11.

FIG. 3 shows a light-emitting element 3 containing the supportivesubstrate 17; the bonding layer 15 formed on the supportive substrate17; the reflective layer 13 formed on the bonding layer 15; thetransparent layer 18 formed on the reflective layer 13; thelight-emitting stacked layer 12 formed on the transparent layer 18,wherein the plurality of contact parts 16 and the etching-stop layer 11are formed between the light-emitting stacked layer 12 and thereflective layer 13 and are surrounded by the transparent layer 18. Aportion of the light-emitting stacked layer 12 is removed to expose aportion of the first semiconductor layer 122, and the etching-stop layer11 is formed under the bottom surface of the light-emitting stackedlayer 12. The plurality of contact parts 16 and the etching-stop layer11 can physically contact the reflective layer 13. The through-hole 19is formed on the exposed portion of the first semiconductor layer 122and extends through the first semiconductor layer 122 to expose aportion of the etching-stop layer 11. The first electrode 21 can beformed on the part of the light-emitting stacked layer 12 where thesecond electrode 22 and the plurality of conductive parts 20 are notformed, extend along the sidewall of the light-emitting stacked layer12, and electrically connect with the etching-stop layer 11. The firstelectrode 21 can also optionally fill the through-hole 19 toelectrically connect with the etching-stop layer 11. Moreover, there canbe a conductive layer 32 which is formed on the light-emitting stackedlayer 12 extending along the sidewall of the light-emitting stackedlayer 12, and filling the through-hole 19 to electrically connect withthe etching-stop layer 11; wherein the first electrode 21 is formed onthe light-emitting stacked layer 12 and the conductive layer 32 toelectrically connect with the etching-stop layer 11. The sidewall of thelight-emitting stacked layer 12 is free of being enclosed by thelight-emitting stacked layer 12. The conductive layer 32 can be metalmaterial and be formed by electroless plating. The metal materialincludes but is not limited to Cu, Al, In, Sn, Au, Pt, Zn, Ag, Ti, Ni,Pb, Pd, Ge, Cr, Cd, Co, Mn, Sb, Bi, Ga, Tl, Po, Ir, Re, Rh, Os, W, Li,Na, K, Be, Mg, Ca, Sr, Ba, Zr, Mo, La, Cr—Au, Ag—Ti, Cu—Sn, Cu—Zn,Cu—Cd, Sn—Pb—Sb, Sn—Pb—Zn, Ni—Sn, Ni—Co, Au alloy, and so on. Theconductive layer 32 can improve the quality of the formation of thefirst electrode 21 to enhance the electrical connection between thefirst electrode 21 and the etching-stop layer 11.

As FIG. 4 shows, a light-emitting device 4 includes at least a firstlight-emitting element 41 and a second light-emitting element 42 locatedcommonly on a supportive substrate 17. The first light-emitting element41 and the second light-emitting element 42 are similar to thelight-emitting element 2. The difference is that the bonding layer 15 isfurther formed between the first light-emitting element 41 and thesecond light-emitting element 42 to separate the first light-emittingelement 41 and the second light-emitting element 42, and the material ofthe bonding layer 15 can be insulating material. The bonding layer 15can physically contact at least one of the contact parts 16. Aninsulating layer 43 is formed on portions of a lateral side and the topsurface of the second light-emitting element 42 which are near the firstlight-emitting element 41. A metal line 44 is formed on the insulatinglayer 43 and the bonding layer 15 to electrically connect at least oneof the contact parts 16 of the first light-emitting element 41 to thesecond electrode 22 of the second light-emitting element 42. The metalline 44 can further contact a portion of the light-emitting stackedlayer 12 of the second light-emitting element 42 in another embodiment.The first light-emitting element 41 and the second light-emittingelement 42 do not contain the first electrodes 21 shown in otherembodiments.

The material of the insulating layer 43 can be insulating material suchas PI, BCB, PFCB, MgO, Su8, epoxy, acrylic resin, COC, PMMA, PET, PC,polyetherimide, fluorocarbon polymer, glass, Al₂O₃, SiO_(x), TiO₂,SiN_(x), or SOG. The material of the metal line 44 can be metal materialsuch as Cu, Al, In, Sn, Au, Pt, Zn, Ag, Ti, Ni, Pb, Pd, Ge, Cr, Cd, Co,Mn, Sb, Bi, Ga, Tl, Po, Ir, Re, Rh, Os, W, Li, Na, K, Be, Mg, Ca, Sr,Ba, Zr, Mo, La, Cr—Au, Ag—Ti, Cu—Sn, Cu—Zn, Cu—Cd, Sn—Pb—Sb, Sn—Pb—Zn,Ni—Sn, Ni—Co, Au alloy, and so on.

As FIG. 5 shows, a light-emitting device 5 is similar to thelight-emitting device 4. Each of the first light-emitting element 41 andthe second light-emitting element 42 of the light-emitting device 5further includes a current-blocking layer 52 formed between thelight-emitting stacked layer 12 and the transparent layer 18.

The plurality of contact parts 16 surrounds the current-blocking layer52. The current-blocking layer 52 is located right under the secondelectrode 22 and can include a plurality of extension portions (notshown here) similar to the second electrode 22. The metal line 44electrically connects the transparent layer 18 of the firstlight-emitting element 41 to the second electrode 22 of the secondlight-emitting element 42. The material of the current-blocking layer 52can be insulating material such as PI, BCB, PFCB, MgO, Su8, epoxy,acrylic resin, COC, PMMA, PET, PC, polyetherimide, fluorocarbon polymer,silicone, glass, Al₂O₃, SiO_(x), TiO₂, SiN_(x), SOG, and so on.

FIG. 6 illustrates a diagram of a light-generating device. Alight-generating device 6 includes a chip manufactured by a wafercontaining the light-emitting element or the light-emitting device ofany one of the embodiments of the present application. Alight-generating device 6 can be an illumination device such as a streetlight, a lamp of vehicle, or an illustration source for interior. Thelight-generating device 6 can be also a traffic sign, or a backlight ofa backlight module of an LCD. The light-generating device 6 includes alight source 61 adopting the foregoing light-emitting elements orlight-emitting devices; a power supplying system 62 providing current tothe light source 61; and a control element 63 controlling the powersupplying system 62.

FIG. 7 illustrates a cross-sectional schematic diagram of a back lightmodule 7. A back light module 7 includes the light-generating device 6of the foregoing embodiment, and an optical element 71. The opticalelement 71 can process the light generated by the light-generatingdevice 6 for LCD application, such as scattering the light emitted fromthe light-generating device 6.

Although the present application has been explained above, it is not thelimitation of the range, the sequence in practice, the material inpractice, or the method in practice. Any modification or decoration forpresent application is not detached from the spirit and the range ofsuch.

What is claimed is:
 1. A light-emitting device comprising: a supportivesubstrate; a transparent layer formed on the supportive substrate, andthe transparent layer comprising conductive metal oxide material; areflective layer between the supportive substrate and the transparentlayer; a light-emitting stacked layer comprising an active layer formedon the transparent layer; an etching-stop layer formed between thelight-emitting stacked layer and the supportive substrate and contactingthe transparent layer; and a first electrode on the transparent layerand electrically connecting to the etching-stop layer, wherein athickness of the etching-stop layer is thicker than that of thetransparent layer in a cross section view of the light-emitting device.2. The light-emitting device of claim 1, wherein the etching-stop layerphysically contacts with a bottom surface of the light-emitting stackedlayer.
 3. The light-emitting device of claim 1, further comprising aplurality of contact parts between the light-emitting stacked layer andthe transparent layer.
 4. The light-emitting device of claim 1, whereinthe supportive substrate comprises a material which is transparent to alight emitted from the light-emitting stacked layer.
 5. Thelight-emitting device of claim 1, further comprising a through-hole inthe light-emitting stacked layer, and the first electrode physicallycontacting the etching-stop layer by the through-hole.
 6. Thelight-emitting device of claim 5, wherein the through-hole is devoid ofpassing through the active layer.
 7. The light-emitting device of claim3, wherein the etching-stop layer and the plurality of the contact partsare on a same horizontal level in a cross-sectional view.
 8. Thelight-emitting device of claim 1, wherein the light-emitting stackedlayer comprises a first region and a second region smaller than thefirst region, and the first electrode covers the second region.
 9. Thelight-emitting device of claim 1, wherein a side surface of theetching-stop layer is covered by the transparent layer.
 10. Thelight-emitting device of claim 1, wherein further comprising a secondelectrode having a second top surface away from the supportive substrateon the transparent layer, wherein a first top surface of the firstelectrode is away from the supportive substrate and lower than thesecond top surface of the second electrode.
 11. The light-emittingdevice of claim 3, wherein the plurality of contact parts comprises aconductive material selected from a group consisting of Cu, Al, In, Sn,Au, Pt, Zn, Ag, Ti, Ni, Pb, Pd, Ge, Cr, Cd, Co, Mn, Sb, Bi, Ga, Tl, Po,Ir, Re, Rh, Os, W, Li, Na, K, Be, Mg, Ca, Sr, Ba, Zr, Mo, La, GeAu,CrAu, Ag—Ti, Cu—Sn, Cu—Zn, Cu—Cd, Sn—Pb—Sb, Sn—Pb—Zn, Ni—Sn, Ni—Co, Aualloy, Ge—Au—Ni, AlGaAs, GaN, GaP, GaAs, and GaAsP.
 12. Thelight-emitting device of claim 3, wherein each of the plurality ofcontact parts is separated from each other.
 13. The light-emittingdevice of claim 3, wherein one of the contact parts comprises a top-viewshape of a triangle, a rectangle, a trapezoid, or a circle.
 14. Thelight-emitting device of claim 3, wherein the light-emitting stackedlayer comprises, in addition to the active layer, a first semiconductorlayer and a second semiconductor layer, and a ratio of the area of theplurality of contact parts to the area of a top surface of the activelayer is 0.5^(˜)6%.
 15. The light-emitting device of claim 1, whereinthe transparent layer comprises a conductive material selected from agroup consisting of ITO, InO, SnO, CTO, ATO, AZO, ZTO, GZO, ZnO, AlGaAs,GaN, GaP, GaAs, GaAsP, IZO, Ta₂O₅, GZO, and DLC.
 16. The light-emittingdevice of claim 1, wherein the transparent layer and the reflectivelayer form an omnidirectional reflector (ODR).
 17. The light-emittingdevice of claim 2, wherein the transparent layer physically contacts thebottom surface of the light-emitting stacked layer.
 18. A light-emittingdevice comprising: a supportive substrate; a transparent layer formed onthe supportive substrate, and the transparent layer comprisingconductive metal oxide material; a light-emitting stacked layercomprising an active layer formed on the transparent layer; a bondinglayer formed between the light-emitting stacked layer and the supportivesubstrate; an etching-stop layer formed between the light-emittingstacked layer and the supportive substrate and contacting thetransparent layer; a through-hole in the light-emitting stacked layer;and a first electrode on the transparent layer and physically contactingthe etching-stop layer by the through-hole, wherein a thickness of theetching-stop layer is thicker than that of the transparent layer in across section view of the light-emitting device.
 19. A light-emittingdevice comprising: a supportive substrate; a transparent layer formed onthe supportive substrate, and the transparent layer comprisingconductive metal oxide material; a reflective layer between thesupportive substrate and the transparent layer; a light-emitting stackedlayer comprising an active layer formed on the transparent layer; and anetching-stop layer formed between the light-emitting stacked layer andthe supportive substrate and contacting the transparent layer, wherein athickness of the etching-stop layer is thicker than that of thetransparent layer in a cross section view of the light-emitting device,wherein the transparent layer and the reflective layer form anomnidirectional reflector (ODR).